Biomass-derived grinding aids

ABSTRACT

Compositions and methods for increasing grinding efficiency of cement, cement clinker, raw materials for cement, and other inorganic particles. Use of biomass-derived polyols such as diols, triols, or mixtures thereof, optionally with a conventional grinding aid, cement quality improver, and/or hexavalent chromium reducer, are believed to provide less risk of sludging when compared to glycerides obtained from fossil fuel sources.

This is a continuation application based on Ser. No. 13/785,657, filedMar. 5, 2013, which was a divisional application based on Ser. No.13/035,164, filed Feb. 25, 2011, which was a divisional applicationbased on Ser. No. 11/434,018, which issued as U.S. Pat. No. 7,922,811B2, which claimed benefit of provisional application No. 60/686,803filed Jun. 2, 2005.

FIELD OF THE INVENTION

The present invention relates to methods and compositions pertaining tothe grinding of cement and cementitious materials, such as cementclinker to produce cement, raw materials for making cement clinker,blast furnace slag, and other particulates; and, more particularly, tothe use in grinding operations of compositions and methods employingpolyols (e.g., diols, and/or triols) that are derived from theconversion of biomass sources such as plant and animal materials.

BACKGROUND OF THE INVENTION

In the process of manufacturing hydraulic cements such as Portlandcement, a grinding operation is used to reduce cement particles torelatively smaller particle sizes. A spherical starting material called“clinker,” which essentially consists of hydraulic calcium silicates,calcium aluminates, and calcium aluminoferrite, is mixed with smallamounts of gypsum and ground into finely divided particles. As thegrinding of clinker to produce the cement consumes substantialquantities of time and energy, it is common practice in the cementindustry to employ grinding aids which increase the efficiency of thegrinding operation, thereby lowering the power required to grind a unitof cement or alternatively, to increase the output of cement toaccommodate high cement demands. The addition of a grinding aid enablesthe mill to grind the clinker to a smaller size with less energy byprohibiting the buildup of a coating of finer material on the grindingmedia and walls of the mill by coating the nascent surfaces of thecement clinker.

In U.S. Pat. No. 3,615,785, Moorer et al. disclosed the use ofpolyglycerols as additives for the grinding manufacture of hydrauliccement, and preferably polyglycerols selected from the group of di-,tri-, and tetraglycerol and mixtures thereof.

The term “glycerol” is often used interchangeably with the terms“glycerin” and “glycerine.” However, more properly speaking, the term“glycerol” applies to the pure chemical compound 1,2,3-propanetriol,while the terms “glycerin” and “glycerine” apply to the purifiedcommercial products normally containing 95% or more of glycerol. A largeportion of the commercial supply of glycerin is produced by esterifyingfats with methanol in the production of methyl esters. The presentinventors believe that such glycerin has been used as an admixture incement and concrete compositions, but until the present inventionglycerin esterified from animal or plant fats has not been used as agrinding aid for cements, cement clinker, or other raw materials usedfor making cement.

Crude and waste glycerins obtained as a by-product (though not relatedto biofuel production as in the present invention) have been usedpreviously for cement grinding. One such glycerol blend was described inSU-1604773. A crude polyglycerin derived from fossil fuel processing waspreviously used by W. R. Grace & Co.-Conn. in grinding aid additiveformulations sometime in the 1980's. However, the purity of the glycerinin terms of glycerol level was about 50%, and thus care was neededduring formulation with other grinding aid components to preventsludging. Other uses of glycerin residues, crude glycerins, and wasteglycerins in cement applications are described in SU-1271843 andSU-1130548. These materials are believed to contain glycerols of variousmolecular weights, and most contain salts such as sodium chloride in aquantity up to 15%. The high level of polyglycerins reduces the grindingaid efficiency of crude glycerins obtained from such processes.

SUMMARY OF THE INVENTION

The present inventors have discovered that the use of polyols,preferably low molecular weight diols and/or triols which are derivedfrom the conversion of biomass sources (“biomass-derived polyols”),provides advantages when compared to glycerins derived from fossil fuelsources in terms of enhancing the efficiency of grinding processeswherein cement, cement clinker, raw materials such as blast furnaceslag, limestone, clay, shale, sand, and others are ground into finerparticle sizes.

For example, a preferred biomass-derived glycerin obtained from themanufacture of biodiesel fuel and be suitably used as a cement grindingaid. This biomass-derived glycerin is believed to provide an advantagefor grinding cement and other materials, as compared to glycerin derivedfrom fossil fuels, because it has higher amounts of pure glycerol. Italso is believed to have less of a tendency to sludge because it is lesslikely to have detrimental amounts of higher molecular weight componentssuch as polyglycerols (wherein two or more glycerol groups are connectedby ether linkages).

From an economic perspective, it is often advantageous to employ lowcost streams of small polar organic molecules as a cement grinding aid.Although the cost of petroleum based fuel is still less expensive forconsumers than biofuels produced from vegetable and plant materials,biofuel-derived glycerin involves renewable natural resources, a factthat may well be more attractive to cement manufacturers in the nearfuture.

Biomass-derived polyol cement grinding aids of the present invention arealso believed to inhibit pack setting of the cement and cementitiousparticles after grinding. In other words, the biomass-derived polyolsare also believed to reduce the amount of energy that might be necessaryto initiate flow in the cement, and this is important when unloading thedry cement powder from storage silos or bins, or after shipment of thecement in trucks, barges, or railroad hopper cars. This tendency to packset is inhibited by reduction in the high surface energy of the cementproduced upon grinding.

An exemplary method of the invention thus comprises introducing toinorganic particles (to be ground into finer particle sizes) a grindingaid composition comprising at least one biomass-derived polyol selectedfrom diols, triols, or mixture thereof.

A preferred grinding aid composition of the invention comprises at least50-95% and more preferably at least 80% level glycerol(1,2,3-propanetriol) contained in glycerin derived from a biomasssource. This biomass-derived polyol-containing composition may be addedseparately or together with one or more conventional cement grindingaids, and/or one or more conventional cement quality improvers (e.g.,cement hydration control agent), and/or other cement additives such ashexavalent chromium reducing agents, and added into the grinding milloperation during or before the grinding of the particles.

Another exemplary grinding aid composition of the invention comprises(A) a biomass-derived polyol, such as glycerin derived from biofuelproduction; and (B) at least one additional component (i.e.,conventional cement additive) selected from the group consisting ofglycol (where the polyol is glycerol); triethanolamine, acetic acid orsalt thereof, triisopropanolamine, sodium acetate,diethanolisopropanolamine, tetrahydroxylethylene diamine, carbohydrates,polycarboxylate ethers, air entraining agents, chloride, nitrite, andnitrate.

A further exemplary grinding aid composition of the invention comprises(A) a biomass-derived polyol, such as glycerin derived from biofuelproduction; and (B) at least one water-reducing additive. Exemplarywater-reducing additives comprise lignosulfonate (e.g., calciumlignosulfonate), a naphthalene sulfonate formaldehyde condensate, amelamine sulfonate formaldehyde condensate, or mixture thereof.

A still further exemplary grinding aid composition of the inventioncomprises (A) a biomass-derived polyol, such as glycerin derived frombiofuel production; and (B) at least one hexavalent chromium reducer.

The use of crude biomass-derived polyols, such as crude glycerin derivedfrom inedible tallow or refined soybean oil, for example, may have highamounts of fatty acids which might make them unsuitable for grindingcement clinker to produce cement, but this particularly crude form ofthe glycerin is believed to be suitable for the milling of rawmaterials, such as limestone, clay, shale, and/or sand which is used formaking clinker.

In still further grinding aid compositions of the invention, abiomass-derived polyol may be used in combination with at least oneother additive, or combination of additives, comprising a conventionalcement additive, a water-reducing additive, and/or a hexavalent chromiumreducer.

Methods which incorporate the aforementioned compositions into grindingoperations, along with further advantages, features, and embodiments ofthe invention, are described in further detail hereinafter.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The term “biomass” means any organic matter available on a renewablebasis, including dedicated energy crops and trees, agricultural food andfeed crops, agricultural crop wastes and residues, wood wastes andresidues, aquatic plants, animal wastes, municipal wastes, and otherwaste materials.

The term “biofuel” as used herein may be used interchangeably with theterm “biodiesel fuel” herein.

The term “grinding” shall include milling or comminution of particles toreduce their average size and to increase the surface area per unit massof material. Methods of the invention for grinding particles include theuse of rotating ball mills or rotary kilns in which the particles arepulverized. The methods may also involve mills which employ rollers(rotating cylinders) for crushing the particles. For example, therollers may be used in a paired, nipped configuration, through which theparticles are passed and crushed. The rollers may alternatively be usedupon a horizontal surface, such as a circular table, on which a bed ofparticles are crushed as the rollers are rotated over the table surface.

The term “particles” as used herein includes hydratable cement andcement clinker which is ground, often with gypsum and calcium sulfate,to produce hydratable cement. The present invention not only concernsthe grinding of clinker to produce cement, and the grinding of cementparticles into still finer particles, but also the grinding of the rawmaterials which go into the production of the cement clinker. Such rawmaterials are commonly known to include calcite, limestone, aragonite,sea shells, marl, limonite, clay, shale, sand, and bauxite. See e.g.,Concrete Admixtures, Vance Dodson (Van Nostrand Reinhold, New York, N.Y.1990), page 4.

As previously mentioned, the present invention involves the use ofpolyols derived from the conversion of biomass sources such as animaland/or plant materials for the purpose of grinding inorganic particlesinto smaller particle sizes.

Biomass-derived polyols of this invention may include the water-solublediols such as ethylene glycol, propylene glycol, polyethylene glycol,polypropylene glycol, diethylene glycol, triethylene glycol, dipropyleneglycol and tripropylene glycol, mixtures of any or all of these glycols,their derivatives, and reaction products formed by reacting ethylene andpropylene oxide or polyethylene glycols and polypropylene glycols withactive hydrogen base compounds (e.g., polyalcohols, polycarboxylicacids, polyamines, or polyphenols). Other glycols contemplated for usein the present invention include neopentyl glycol, pentanediols,butanediols, and such unsaturated diols as butyne diols and butenediols. Most preferred are the polyglycols of ethylene and propylene.

The derivation of polyols from biomasses has been achieved on anindustrial scale for quite some time. For example, International PolyolChemicals, Inc. (“IPCI”) began two decades ago to focus on developingnew “green” chemical process technology to produce industrial glycols(such as ethylene glycol, propylene glycol, butanediols and glycerin)from sugars of any type. Previously these products came primarily frompetroleum sources. In tropical areas, tapioca, cane sugar, and molassesare preferred. Unusual sugars, such as lactose, which is a cheesemanufacturing whey by-product, is also a potential feedstock candidate.Plant or vegetable fibers as well can be either enzyme or acidhydrolyzed to sugars which also can be a feedstock in glycol production.The IPCI process is believed to have two basic steps: namely, (1)continuous catalytic hydrogenation of glucose or monomer sugars tosorbitol; and (2) continuous catalytic hydrocracking of sorbitol toglycols. The resultant glycols are then usually separated bydistillation, and typically used in the food, cosmetic, andpharmaceutical industries. The present inventors believe that suchbiomass-derived polyols can be used for enhancing the grinding ofcement, cement clinker, raw materials such as slag, and other particlesinto finer particulate sizes.

Another biomass source for providing polyols for purposes of theinvention is animal manure. With 160 million tons of it producedannually in the United States, most of it rich in carbohydratecomponents, the present inventors view this as a source of five- andsix-carbon sugars that can be converted to diols and/or triols throughany number of known catalytic means. This process, of course, is lessdesirable than using agricultural biomass feedstocks, such as wheatwastes, which are comprised mostly of clean carbohydrates. The PacificNorthwest National Laboratory (“PNNL”), a U.S. Department of Energyfacility in Washington State, has been successful in converting animalwastes into chemicals and has developed various catalytic approaches forconverting other low-value biobased materials to chemicals, such as thewastes and by-products resulting from processing corn, wheat, potatoesand dairy products. Such by-products, if not in a diol or triol form,can be converted into diols and/or triols, through known methods.

Biomass-derived triols may be obtained from the processes above, but themost preferred triol is glycerol obtained as a by-product from theproduction of biofuel because of the high levels of glycerol, and, aspreviously mentioned, relatively low or non-existent levels ofpolyglycerides. If polyglycerides are also to be present along with pureglycerol from conversion of the particular biomass source, then theinventors prefer smaller glycerides over larger ones (i.e., diglyceridesbeing most preferred).

“Biofuel-derived polyols” such as glycerin (which contains glycerol) areamong the preferred biomass-derived polyols of the present invention.Processes for making biofuels from plant and/or animal oils are known,and crude glycerins useful as grinding aids can be obtained as a directby-product from such processes (e.g., precipitation). For example, thetransesterification of plant and animal oils to produce biofuels isdescribed by Demirbas in ‘Biodiesel Fuels From Vegetable Oils ViaCatalytic and Non-Catalytic Supercritical Alcohol TransesterificationAnd Other Methods: A Survey.” A process for transesterification ofvegetable or animal oils is also described in European PatentApplication EP 1 505 048 A1 of Thierry Lacome et al. A variety of plantand animal sources, which can be used for making biofuels, can also befound in the literature.

Transesterification is the process of using an alcohol (e.g., methanol,ethanol, butanol) in the presence of a catalyst, such as sodiumhydroxide or potassium hydroxide, to break the molecule of the rawrenewable oil chemically into methyl or ethyl esters of the renewableoil, with glycerol as a by-product. Biodiesel, which is made ofmono-alkyl esters of fatty acids derived from vegetable oil or animalfat, can then be separated from the glycerin, usually as a result of theaddition or presence of salts after the transesterification reaction(e.g., Triblycerides+Monohydric alcohol>Glycerin+Mono-alkyl esters). Thetransesterification can be alkali catalyzed, acid catalyzed, and cantake place in ethanol or methanol. Demirbas also describes formulationof biofuel through saponification and pyrolysis with glycerin as abyproduct.

The crude glycerins favored in the present invention need notnecessarily be limited to biofuel derivation, however. The presentinventors believe that any glycerol from glycerides (natural glycerol)derived from plant or animal sources through soap manufacture, fattyacid production, and fatty ester production can yield various amounts ofcrude glycerins. However, the present inventors believe that fatty esterproduction provides the highest level of glycerol; and thereforeglycerins as the by-product of fatty ester production is most preferred.Glycerins derived from fatty ester production often have acceptablelevels of chloride salts (up to 15% by total weight) which are notbelieved to be detrimental to the final ground cement product forpurposes of the present invention.

Samples of crude glycerin obtained from the production of biofuels canhave purity levels up to 92% and even 95% glycerol, the remainderbelieved to comprise salts such as sodium and/or potassium chloride, andthus do not require purification, as is often the case with fossil-fuelderived glycerins.

In exemplary grinding aid compositions comprising biomass-derived diols,triols, or mixture thereof, such biomass-derived portion shouldpreferably have an average molecular weight of about 50-200. Indeed, ifdiols and triols are blended together, the present inventors believethat it may be possible that the composition will be applicable as agrinding aid over a wider range in cement types, for example.

Exemplary compositions of the present invention thus comprise: (A) atleast one biomass-derived diol, at least one biomass-derived triol, or amixture thereof; and (B) at least one conventional grinding aidcomponent such as a glycol (where component A is a glycerol),triethanolamine, acetic acid or salt thereof, triisopropanolamine,sodium acetate, diethanolisopropanolamine, tetrahydroxyethylethylenediamine, carbohydrates, polycarboxylate ethers, air entraining agents,as well as chloride salt, nitrite salt, or nitrate salt. For example,component A may comprise 10-90% while component B comprises 90-10%, allpercentages based on weight of the composition,

In preferred grinding methods and grind aid compositions of theinvention, a biomass-derived polyol such as biofuel-derived crudeglycerin should preferably contain a little or no ash. The amount of ashshould preferably be less than 50%, more preferably less than 15%, andmost preferably less than 10%. The amount of ash may be described interms of nonglycerol organic matter, or “MONG,” which is an acronym for“Matter Organic NonGlycerol.” MONG is believed to include fatty acidsand esters, trimethylene glycol (TMG), ie. propane-1,3-diol; water;arsenic; and sugars.

Thus, an exemplary composition of the present invention may comprise abiomass-derived diol (10-90%), a biomass-derived triol (90-10%), and aMONG content of 0.005-50%.

A preferred biofuel-derived glycerin suitable as a cement grinding aidis believed to be available from World Energy company. Although thesource of the plant or vegetable oil is not known, the glycerin fromWorld Energy is said to contain the following components: glycerin(88%), methanol (0.05%), moisture (8%), total fatty acid content (0.2%),sodium chloride (2%), and “ash” (3%) with a pH of around 6 and sulfateand phosphate content each around 300 parts per million.

Another preferred biofuel-derived glycerin is available from ImperialWestern Products, and is believed to be derived from spent fryer grease.This crude glycerin contains the following components: glycerin(91.57-92.19%), methanol (<0.01%), moisture (4.05-5.77%), anunsaponifiable portion (0.056%), and ash 1.03-1.61%), and an insolubleportion of 0.28%).

Another glycerin which is believed to be suitable for cement grindingaid purposes, derived from soapmaking, wherein the source is 85% tallowoil and 15% coconut oil, is available from Trillium Health CareProducts—Perth Soap, and contains the following components: glycerin(80%), moisture (12%), sodium chloride (8%), and ash (11%), with a pH of7-11 and sulfate content of about 2500 parts per million.

A further aspect of this invention is that biomass-derived polyolswhich, on the one hand, may not be entirely suitable for grinding cementclinker into finished hydratable cement due to low glycerol content, maybe suitable for less refined milling or grinding operations, such aswhere raw materials such as calcite, limestone, aragonite, sea shells,marl, limonite, clay, shale, sand, or bauxite, or a mixture of any ofthese, are ground in a mill or rotary kiln to produce the cementclinker. Thus, for “raw materials” grinding processes, it is believedsuitable to use a biomass-derived polyol available from South TexasBlending company which is derived from inedible tallow and whichcomprises approximately 50% glycerin with the remainder believed to be ahigh level of fatty acids. Another biomass-derived polyol is alsobelieved to be available from Soy Solutions comprising glycerin (51%),methanol (6%), and “MONG” (45%).

Preferred exemplary grinding aid compositions of the invention comprisethe following components in the percentage ranges indicated (based ontotal weight of the compositions):

-   -   Embodiment 1: water (10-30%), triethanolamine (10-80%), and        biofuel-derived glycerin (10-80%).    -   Embodiment 2: water (10-30%), triisopropanolamine (10-80%), and        biofuel-derived glycerin (10-80%).    -   Embodiment 3: water (0-40%), tin sulfate (40-70%), and        biofuel-derived glycerin (10-60%).    -   Embodiment 4: calcium nitrate (20-40%), calcium nitrite        (15-30%), calcium bromide (2-5%), biofuel-derived glycerin        (2-10%), and water (25-41%).    -   Embodiment 5: water (15-65%), sucrose (10-30%), lauryl ether        sulfate (5-15%), and biofuel-derived glycerin (20-40%).

In further exemplary compositions and methods of the invention, thebiomass-derived polyols (e.g., biofuel-derived glycerin) can be modifiedby reacting the polyol (e.g., diol such as glycol or triol such asglycerol) with a monobasic carboxylic acid (e.g., acetic acid) toenhance the efficiency of the cement grinding operation. For example,U.S. Pat. No. 4,643,362 of Serafin (owned by the common assignee hereof)taught that diesters formed by reacting a polyol, e.g., mono andpolyalkyl diols and triols with a monobasic carboxylic acid (e.g.,acetic acid, formic acid, propionic acid) are excellent grinding aids inthe grinding of hydraulic cements such as Portland cement. Thus, thepresent inventors believe that the Serafin modification can also be usedto modify biomass-derived polyols of the present invention, includingbiofuel-derived glycerin, to achieve excellent grinding aids.

In still further exemplary compositions and methods of the invention,the biomass-derived polyols, such as biofuel-derived glycerin, can besubstituted, such as by substituting for any of the alcohol radicals(OH), a suitable element or group, such as one of the halogens or anorganic ester group. The concept of using substituting glycerols forimproving cement grinding efficiency, as well as the properties of thefinished cement, was disclosed in U.S. Pat. No. 2,203,809 by Bechtold.The present inventors believe that biomass-derived polyols such as diolsand/or triols can be substituted using the Bechtold method to providegood cement grinding efficiency. Thus, preferred biomass-derived polylsinclude glycerol monochlorohydrin and other like halogen substitutioncompounds, glycerol mono acetic ester and other corresponding esters ofthe thyl, propyl, butyl series. Glycerol mono acetic ester is known alsoas mono-acetin, which has the alpha and beta isomeric forms, either orboth of which are believed to be suitable.

The amount of grinding aid can vary within wide limits, but preferably0.001 to 1.0% by weight (of additive solids) and more particularly 0.005to 0.05%) by weight of grinding aid is used, based on the weight of themineral solids (i.e., “solids on solids” or “s/s”) that are subjected togrinding. There is no upper limit for the added grinding aid quantity,but, in general, only that quantity required for obtaining the desiredsurface area in the most efficient mill operation is added.

The biomass-derived polyol grinding aids of the present invention arepreferably added alone, but can also be added together with one or moreconventional grinding aids, as have been aforementioned, or with otheradditives.

Further exemplary compositions and methods of the invention furthercomprise the use of at least one biomass-derived polyol and at least onehexavalent chromium reducing agent, including iron sulfate, tin sulfate,sodium sulfide, sodium sulfite, sodium bisulfite, hydroxylamine sulfate,sodium dithionate, manganese sulfate, an aldehyde, or a mixture thereof.

In further exemplary grinding aid compositions and methods of theinvention, at least one (A) biomass-derived polyol may be combined withat least one additive or a mixture of additives selected from (B)conventional cement additives, (C) water-reducing additives, and/or (D)hexavalent chromium additives.

For example, a bio-fuel derived glycerin may be combined with aconventional cement additive such as triethanolamine,triisopropanolamine, or mixture thereof; a water-reducing additive suchas a lignosulfonate (e.g., calcium lignosulfonate), naphthalene,sulfonate formaldehyde condensate, melamine sulfonate formaldehydecondensate, or a mixture thereof; a hexavalent chromium reducer such asioron sulfate, tin sulfate, sodium sulfide, sodium sulfite, sodiumbisulfite, hydroxylamine sulfate, sodium dithionate, manganese sulfate,an aldehyde, or a mixture thereof; or any combination of suchcomponents.

In further methods of the invention, the biomass-derived polyol may beselected such that it is substantially free of diol, and thus maycomprise biomass-derived glycerin (such as biofuel-derived glycerin),and employed as a grinding aid in a raw mill for making cement clinker.

The foregoing discussion is provided for illustrative purposes only, andnot intended to limit the scope of the invention.

We claim:
 1. A method for increasing efficiency of grinding cementclinker particles or limestone particles, comprising: introducing tocement clinker particles, limestone particles, or mixture thereof, in arotating ball mill or rotating roller mill whereby said particles areground to have finer average particle size, an aqueous additivecomposition comprising: at least one grinding additive selected from thegroup consisting of triethanolamine, triisopropanolamine,diethanolisopropanolamine, tetrahyroxyethylthylene diamine, an aceticacid or salt thereof, or mixtures thereof; and a crude glycerin obtainedderived from biofuel production comprising glycerin, methanol, watermoisture, fatty acid, sodium chloride, sulfate, phosphate, and ash, saidash being present in an amount not exceeding 10% by weight of theaqueous additive composition; wherein the amount of said at least onegrinding additive and said crude glycerin derived from biofuelproduction being in the ratio of 90:10 to 10:90 by weight.
 2. The methodof claim 1 wherein said aqueous additive composition comprising at leastone grinding additive and said crude glycerin derived from biofuelproduction are introduced together as a single additive composition, theadditive composition comprising water in the amount of 10%-30% andtriethanolamine in an amount of 10%-80%, and said crude glycerin derivedfrom biofuel production comprising 1,2,3-propane triol.
 3. The method ofclaim 2 wherein said aqueous additive composition comprising at leastone grinding additive and said crude glycerin derived from biofuelproduction are introduced together as an additive composition, theadditive composition comprising water in the amount of 10%-30% andtriisopropanolamine in an amount of 10%-80%, and biofuel derived1,2,3-propane triol.
 4. The method of claim 3 wherein the1,2,3-propanetriol within said byproduct is reacted with a monobasiccarboxylic acid.
 5. The method of claim 3 wherein the 1,2,3-propanetriolwithin said byproduct has one or more substituted OH groups.
 6. Aparticulate composition made by the method of claim
 1. 7. A compositionfor increasing efficiency of grinding particles, comprising: at leastone grinding additive selected from the group consisting oftriethanolamine, triisopropanolamine, diethanolisopropanolamine,tetrahyroxyethylthylene diamine, an acetic acid or salt thereof, ormixtures thereof; and a crude glycerin obtained derived from biofuelproduction comprising glycerin, methanol, water moisture, fatty acid,sodium chloride, sulfate, phosphate, and ash, said ash being present inan amount not exceeding 10% by weight of the aqueous additivecomposition; and the amount of said at least one grinding additive andsaid crude glycerin obtained derived from biofuel production being inthe ratio of 90:10 to 10:90 by weight.